I'll admit that, while I'm writing this, I'm watching the very end of Dragon Ball for the first time, having watched Z and GT first. So... I'll just say that Piccolo isn't a very good guy.
Yamcha had drifted along rather slowly, having considered several times during his flight to turn back. The increasing energies were making him uneasy, but with each disturbance of the air, he felt his curiosity grow. He needed to go to the Lookout and relieve himself of his creeping suspicions that it might actually have been Vegeta up there, but the suspect power level began dwindling when he had just started his journey. There was still one other mysterious power level, though, that was staying still, not fluctuating at all. The only two noticeable power levels, interestingly enough, became Mr. Popo and Piccolo's, though that seemed odd to the man. There was no reason for those two to raise their levels, unless they were fighting...
When he finally got into view of Kami's lookout, he saw Piccolo standing on the edge, presumably looking at the approaching man. But Yamcha was too far away to notice that the expression on the Namekian's face was one of worry, clearly telling him to go away. By the time he was close enough to see these warnings, he had noticed Dende and Mr. Popo crowding around something with a stranger. It was clearly mysterious power level number one accompanying the genie and Namekian, though he couldn't distinguish who the stranger was.
As he reached the perimeter of the Lookout, Piccolo stalked up to him and yelled, "Yamcha! What are you doing here?" It wasn't anger in his voice, but it was concern, something odd coming from the Namekian's mouth.
"I felt an energy, and I thought there might have been trouble," he explained, landing rather unsteadily on the tile before turning to see the others. At this closer angle, what he saw both shocked and disturbed him, making him stumble forward curiously. There were Dende and Mr. Popo and the mysterious third man, purple-skinned with long, white hair. They were hovering over a body on the ground, which came as quite a surprise, but what he noticed next simply scared him. It was Trunks on the ground, all grown up and simply laying there with blood all over his face and clothes, the others making small talk around his body. Before the three around the corpse could react by stopping him, Yamcha hurried to kneel down next to the body and ask, "What... what happened?" His voice was filled with disbelief, seeing his step-son for the first time in several years, and in such dire circumstances.
"Get away from him," Piccolo demanded, grabbing the man and picking him up easily against his will. Then he set an astounded Yamcha back down on his feet. "Go back home. If you don't, you will die."
Yamcha resisted, ignoring this threat and insisting, "But he's my wife's son! I'm in charge of him; let me bring him back to Bulma! She has to see him!" But Piccolo continued blocking his path, finally grabbing the persistent man by his forearms, clenching his claws into his leathered skin. Yamcha's face dropped in agony, first from seeing the fully grown man so damaged, so like his future counterpart, and then from the pain coursing through his body. He dropped to his knees again as Piccolo released him and stared at his arms, both pierced by the Namekian's dangerous claws.
"Now go. He doesn't want to go with you; he wants to kill you."
Yamcha's breathing increased as he looked into the Namekian's cruel eyes, glazed with the truth. The words pained him, though he realized that the Namekian wasn't lying. It made sense that the boy, the man, would want to kill him, having married his mother. He had always been protective and arrogant, self-serving yet always justifying his actions. Trunks had run away, unable to bear seeing another man with his mother, and returned to kill him. Yamcha had never suspected this, but hearing Piccolo and seeing the boy in the flesh brought about these realizations.
He staggered back up to his feet as Dende rushed towards him, also grabbing him by the forearms. But instead of digging his claws into his skin, Dende held the man's arms gently in his grip, a power radiating from his palms. Yamcha watched in amazement as the scars Piccolo had delivered to him began healing, patching themselves up with threads of skin spinning themselves across the wounds. Within a few seconds, there was no evidence that Piccolo had ever assaulted him.
Before Dende could console the confused man with comforting words, though, Piccolo pushed the Namekian out of the way and grabbed Yamcha by his shoulders. Then, with a sudden fierceness, he lunged his hand towards Yamcha's throat and held him in the air, suffocating him.
Kibito Kai was too stunned to react, simply watching in horror as Dende rushed up to Yamcha, trying to pry him from Piccolo's tight, one-handed grip. Mr. Popo only watched, realizing just what the Namekian was doing and disapproving of the method, but going along with it knowing that it was effective. Piccolo snarled, pushing Dende aside again and swinging the choking Yamcha further away, his face flushed from a lack of air. Then, all of the sudden, Yamcha's tensed body became limp.
Everybody watched in awe as Piccolo gently lowered the body, still holding on to it by the throat. Then Dende backed away, afraid, and muttered, "You didn't kill him, Piccolo." It was true; he could hear the faint beat of the man's heart, struggling to survive.
"Of course I didn't kill him," the Namekian replied, setting him down carefully on the ground. He tore his white cape off of his back and began wrapping the man up in it as he said, "My objective wasn't to kill him. He is going to be out cold for a few days, but he'll be fine after that. He's too strong of a human to die like that."
"Why... why did you choke him?" Dende stuttered, unable to comprehend why his friend had just used such a harsh method for knocking him out.
Piccolo chuckled menacingly, his voice coming from the back of his throat. "If I had just hit a pressure point, he would only be out for a few hours." Mr. Popo nodded knowledgeably, allowing the Namekian to continue, "But by choking him, I'm certain that he'll be out for a few days. He may need hospital care, but I think that he'll pull through. I need him to be out for a few days." He stood up from his wrapping job, and, dusting his hands off, turned to his fellow Namekian and asked, "Do you know what an unconscious man doesn't give out?"
"Breath?" Dende guessed uncertainly, but Kibito Kai stepped forth, finally understanding the plan.
"Energy!" the Kai exclaimed jubilantly, recognizing the strategy. Mr. Popo, the only one by Trunks now, nodded as Piccolo said nothing. But Dende still didn't understand exactly what the Kai meant, so he further explained, "If this man doesn't emit energy, then Trunks won't be able to find him." As Dende finally realized that Piccolo wasn't just some nut, the Kai went on to ask curiously, "But who is this man? What was he in danger of?"
Piccolo grimaced as Mr. Popo said, "This man is Yamcha, Trunks' step-father. If Vegeta never does return, it will most likely be Trunks that kills him." And with these grim words, he pointed towards the demi-Saiyan's body.
"Oh!" the Supreme Kai said for lack of better words, his gaze darting between the two unconscious bodies on the floor. Both were terribly near death, one a ghostly white and the other with blood all over his broken face. Then he stared at Piccolo in true amazement, having never met somebody whose techniques of saving lives were quite so brutal.
Eighteen walked outside, surprised as her hair flew up in a rush of air. She persisted through the weather, not affected at all by the chill of night. Then she marched down the beach in her boots, tracing footprints that Chi-Chi had left earlier. She examined the circumference of the island, trying to determine exactly where the demi-Saiyan was coming from. She finally ended up right in front of the house again, facing the east. She placed her hands on her hips, hearing Gohan speeding, parting the waves beneath him. The thought scared her as she stared into the black sky, thin clouds lining it.
She showed no alarm as Goku appeared behind her, asking, "Do you really think he's dangerous?"
"Yes," she said, quite matter-of-factly. She continued looking towards the sound's origin and then asked, startling the man, "How good is your nose?" At this, Goku cocked his head curiously. Seeing his confusion, she clarified, "How well can you smell?"
"I can smell really well!" Goku exclaimed enthusiastically, his mind taken off of the threat his son possessed. "Once, when we were kids, Krillin and I had to go find a rock in the forest, and I used my nose to smell it." His face fell as he remembered the rest of the story, and he said, "Of course, I still lost. Krillin got the rock back to Master Roshi before I could, so I didn't get dinner that night." After thinking for a brief second, he explained, "I bet Krillin has a better nose than I do. He must have been able to smell that rock from a mile away!"
Eighteen smirked, refraining from telling the man that her husband probably cheated. As amusing as the tale was, she brought his focus back to the situation at hand by asking, "Can you smell fear?"
She lost him again with this question, as he replied, "I don't know. What does fear smell like?"
She shook her head, staring up towards the partially cloudy sky. She admitted, "Even I'm not sure, but I think your son's afraid. I can sense it in his movements." She closed her eyes then as she paused before resuming, "I think you should go find him. It is you he wants, and I think you can deal with him. I don't want everybody else to be put at risk for something you did."
"I did?" Goku asked uneasily, scratching the back of his head as he watched the blond android. "I didn't do anything, did I?"
She exhaled deeply, saying, "You changed him, Goku. After you left, he became a different man. I never liked him before, but after your departure, he became more cynical and lonesome." Then, without any remorse, she added, "He became like me."
Goku bit his bottom lip, unaware of these changes in Gohan. Nobody had informed me of this when he was gone, or even when he had returned. And now they were all inside, probably listening to Krillin on the floor trying to crack another joke to lighten the mood. If he had known that his son was so broken, he would have come back and taken charge of the family again. He had just always assumed that everything was all right.
He turned towards Eighteen, finally saying, "I think I will go see him." And, suddenly, he jumped into the air, heading quite slowly in the direction he sensed his son's bulleting energy. The android released a breath, watching the Saiyan fly off. She hoped that Goku's level-headed self would be able to rub off on the furious and uncertain Gohan. If the opposite happened, she knew that things could end badly.